Means for controlling the rate of supply of liquid fuel to prime movers



Oct. 20, 1953 2,655,845

"T. A. HARRIS MEANS FOR CONTROLLING THE RATE OF SUPPLY OF LIQUID FUEL TO PRIME MOVERS Filed May 31,. 1951 Patented Oct. 20, 1953 MEANS FOR CONTROLLING THE RATE OF SUPPLY OF LIQUID FUEL TO PRIME MOVERS Thomas Alfred Harris, Edgbaston, Birmingham, England, assignor to Joseph Lucas Limited, Birmingham, England Application May 31, 1951, Serial No. 229,010

In Great Britain June 6, 1950 3 Claims. 1

This invention relates to means for regulating the rate of supply of liquid fuel to a jet-engine, gas turbine or other prime mover, and has for its object to enable the said means to be controlled from a distance.

The invention comprises the combination of a throttle adapted to control the flow of liquid through an associated passage, a liquid actuated servo-mechanism for actuating the throttle, and electromagnetic means for controlling the servomechanism.

The accompanying drawing illustrates diagrammatically one embodiment of the invention.

Referring to the drawing, there is provided any convenient throttle as 0, adapted to control the rate of flow of liquid fuel supply through an orifice b to a pipe which conveys the fuel from a pump it to the burner e of the prime mover.

The throttle is under the control of a fuelactuated servo-mechanism. This comprises a cylinder f containing a piston g loaded by a spring h, the piston being connected to the throttle a. The ends of the cylinder are in communication with each other through a restricted orifice i which may be provided, as shown, in the piston, or in the cylinder wall, or in a pipe interconnecting the ends of the cylinder. The end of the cylinder 1 remote from the spring h acting on the piston g is adapted for connection with the inflow side of the throttle by a passage The other end of the cylinder is adapted for connection with a fuel supply tank It or the inlet side of the pump d, by way of a pipe or passage m under the control of one or more spring loaded vent valves arranged in parallel. In the example shown in the drawing, two such valves are shown, and indicated by n and each is loaded by a spring 0. Each valve is operable by an electromagnet 12, the excitation of which can be controlled by a switch q. Also the vent passages 1' leading from the cylinder to the said valves are under the control of a piston valve 3 connected to or otherwise operable by the piston g of the servomechanism.

Assuming that it is required to supply liquid fuel to the burner at any one of three rates, two electromagnetically operable valves are provided as shown, and in this example the mode of action is as follows:

Starting with the throttle a at its position of maximum restriction of the orifice b, the quantity of fuel then supplied to the burner is at the minimum required, the fuel being supplied at a constant pressure by the pump at, which ill) 2 pressure may be under the control of a relief valve (not shown). In this condition the piston valve s opens both of the vent passages 1' leading to the electro-magnetically operated vent valves, these being normally closed.

When it is required to increase the speed of the prime mover, the first of the two electromagnetically operated vent valves is opened by excitation of the associated magnet. Liquid can now pass from the servo-motor cylinder, and the preponderating pressure acting on the piston 9 moves the latter in opposition to the spring h for increasing the flow past the throttle. When the throttle has been moved through an appropriate distance, the piston valve s interrupts the flow to the open electromagnetically operated valve, and so prevents further movement of the servo-piston and throttle.

When it is required to cause a still further increase of fuel flow past the throttle, the other electromagnetically operated valve is opened. The servo-mechanism then moves to the next position until arrested by a stop or by the closing (by the piston valve s), of the vent passage 1' leading to the second valve.

The invention is not, however, restricted to the above example, as it may be embodied in other forms. Thus, the throttle may be arranged in a system which is separate from the fuel system, and is provided with its own liquid circulating pump.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. Means for controlling the rate of supply of liquid fuel to a prime mover comprising, in combination, a throttle valve movable in a fuel supply passage for controlling fuel fiow therein, a liquid actuated servo-mechanism including a cylinder and a piston operatively connected with the throttle valve for displacing the latter, a plurality of vent passages communicating with the cylinder, a valve controlling each of said vent passages, separate electromagnetic means for actuating each of said valves in succession, and. a single valve member operatively connected with the piston and movable therewith upon successive actuation of the vent controlling valves to a series of positions for successively controlling the vent passages in a sense opposite to the control exercised by the separate valves upon actuation thereof, whereby the piston of the servo-mechanism is held in a position determined by the number ofvent control valves actuated.

2. Means according to claim 1, in which the 1 2,655,945 3 4 vent controlling valves are normally held in maximum obstruction of fuel flow, and a piston closed position and are opened by the electrovalve movable with the piston and constituting magnetic means, and the single valve member is the single valve member, said piston valve being constituted as a piston valve and is successively movable in the aforesaid coaxial bore for sucmovable to close the vent passages which open 5 cessively closing the ends of the vent passages into a single boretraversedaby?saidapiston valve. "atherein,5the separatemalvestcontrolling the vent 3. Means .caccording to claim 1,-in which the wpassagestbeing-enornially clsed 5 by springs and servo-mechanism comprises a, cylindrical chamopened by actuation of the electromagnetic her having at one end a liquid fuel inlet ancltan itmeans. outlet controlled by the throttle valve; the-other: :10

end of the chamber communicating-with a: bore THOMAS ALFRED HARRIS. coaxial with the chamber into which bore the veiig; passages oaendat spaced P 2 i gg mReferences-Qitefi in the file of this patent or ce means a or mg communic'a ion ween a the two ends of the chamber which constitutes 515, STATES PATENTS the cylinder of the servo-mechanism and .the pis- I Tum.bi V Name Date ton of which is connected toth"throttlejvalve, i-li341629 *Pig' eolet Jan. 19, 1932 a spring acting on the piston inthdiic'tion 2,3'29ZQ01 Robinson Sept. 7, 1943 for moving the throttle valve to a position of 2,546,055 Ballard Mar. 20, 1951 

